CarPlay actually started in 2016
Another thing to note, all 2018 and up Tahoe suburbans have LED Daytime Running Lights (the LED bar) at full brightness on all 2018 and up on all trims (LS, LT etc). 2017 and below use stand halogen DRL low beam on non LTZ non premier models, so something to keep in mind if your not getting a LTZ or premier.
Also note, bench seats in the 2nd row is not available on as an option on any LTZ or premier models, if you want something with this and want the luxury features (push to start, rear heated seats, keyless entry, bentalted front seats) find a LT with a bench but the luxury package, a easy indicator that it has the luxury package for Tahoe or suburban is typical fog lights on a LT, as only lt luxury package an up has fog lights, it was only offered as a package.
In terms of Yukon, they all have LED DRL, all years all trims. Yukon SLT trim all have push to start and fogs lights, the SLT on a Yukon is like LT but with luxury package already.
Always stay away from 2015 models for all models.